Aircraft canopy separation system

ABSTRACT

An aircraft canopy separation system including a frangible member that can comprise tempered glass or a glass ceramic that is connected to the aircraft canopy at a location that will permit the opening or removal of the canopy after the frangible member has disintegrated as a result of being struck by a sharp instrument. The frangible member comprises a rod that is located within a hinge that is attached to the canopy. A sharp-pointed instrument is also provided for striking the frangible member that may be located on an aircraft ejection seat at a point where it will strike the frangible member as the ejection seat is being ejected from the cockpit of the aircraft.

[ 1March 20, 1973 [54] AIRCRAFT CANOPY SEPARATION SYSTEM [75] Inventor:James A. Clarke, Plainview, N.Y.

[73] Assignee: Fairchild Industries, Inc., Montgomery County, Md.

[22] Filed: Feb. 12, 1970 [21] Appl. No; 10,861

[52] US. Cl. ..244/121, 49/141, 70/92, 244/122 AB [51] Int. Cl ..B64c1/14 [58] Field of Search .....244/12l, 122; 102/24; 52/98, 52/99;49/141; 292/327, 92; 287/36 D; 70/92, 422; 285/2 FOREIGN PATENTS ORAPPLICATIONS Great Britain 102/495 Great Britain ..49/141 PrimaryExaminerMilton Buchler Assistant Examiner-Barry L. KelmachterAttorney-Michael W. York [57] ABSTRACT An aircraft canopy separationsystem including a frangible member that can comprise tempered glass ora glass ceramic that is connected to the aircraft canopy at a locationthat will permit the opening or removal of the canopy after thefrangible member has disintegrated as a result of being struck by asharp instrument. The frangible member comprises a rod that is locatedwithin a hinge that is attached to the canopy. A sharp-pointedinstrument is also provided for striking the frangible member that maybe located on an aircraft ejection seat at a point where it will strikethe frangible member as the ejection seat is being ejected from thecockpit of the aircraft.

10 Claims, 9 Drawing Figures AIRCRAFT CANOPY SEPARATION SYSTEM Thisinvention relates to aircraft canopies and more particularly to anaircraft canopy separation system that utilizes a frangible member topermit the rapid opening of the canopy.

Many modern high speed aircraft require a system for rapidly ejecting anairman from the aircraft in the event the aircraft and the airman areendangered due to damage or malfunction of the aircraft. With modernhigh-speed aircraft it is essential that this ejection occur as rapidlyas possible since any delay in departing from the aircraft may preventthe airman from safely exiting the aircraft.

Various systems have been developed to rapidly eject airmen fromaircraft. One well-known system incorporates an explosive charge orother such device that projects the aircraft seat and the airman upwardand out of the aircraft cockpit. With this type of system, it is usuallynecessary to provide an opening in the aircraft canopy through which theairman and the seat can be ejected or to provide a means for jettisoningthe canopy. Unfortunately, the jettisoning of the canopy or removing oropening a portion of it to permit ejection from the aircraft consumestime and effort on the part of the airman and in some instances wherethe canopy or canopy mechanism is damaged, this may not be possible. Inorder to avoid these difficulties, systems have been designed thatproject or fire the airman in his aircraft seat through the canopy. Thistype of system permits the airman to eject from the aircraft withminimal effort even though the canopy cannot be opened. Although thetype of system that fires the airman through the canopy has decidedadvantages, the airman is subject to possible injury as he passesthrough the canopy since present canopies can present serious hazards tothe ejecting airman. Present canopies are designed primarily to protectthe airman during normal flight and thus the impact of the ejecting seatas it strikes the canopy can injure the airman. In addition, thefragments or remaining portions of the canopy can strike and injure theairman as he passes through the canopy.

Many canopy systems do not permit the airman to be readily removed fromthe cockpit by a person outside the aircraft if the canopy openingsystem is damaged as a result of the crash of the aircraft, nor do theypermit the airman to readily remove or open the canopy without ejectingfrom the cockpit when the canopy opening system is damaged.

The aircraft canopy separation system of this invention overcomes thesedisadvantages and permits the airman to safely and rapidly eject himselffrom the aircraft cockpit and permits the removal of the airman fromoutside the aircraft in the event of damage to the canopy openingsystem. In addition, this canopy separation system permits the airman toget out of the cockpit without ejecting in the event the normal canopyopening system is inoperative.

It is therefore an object of the present invention to provide anaircraft canopy separation system that permits the airman to eject fromthe cockpit without removing or jettisoning the canopy prior toejection.

It is also an object of this invention to provide an aircraft canopyseparation system that permits the airman to rapidly eject himself fromthe cockpit.

A further object of this invention is to provide an aircraft canopyseparation system that permits the airman to safely eject from thecockpit.

A further object of this invention is to provide an aircraft canopyseparation system that permits the airman to open the canopy withoutejecting from the cockpit in the event that the normal canopy openingsystem is inoperative.

A further object of this invention is to provide an aircraft canopyseparation system that permits the removal of the airman from thecockpit by a person outside the aircraft in the event the normal canopyopening system is damaged.

The present invention provides an aircraft canopy separation system thatincludes a frangible member connected to the aircraft canopy at alocation that will permit the opening or removal of the canopy when thefrangible member disintegrates after being struck by a sharp instrument.A sharp-pointed instrument is also provided for striking the frangiblemember. This sharppointed instrument can be connected to the aircraftejection seat at a point where it will strike the frangible member asthe aircraft ejection seat is being ejected from the cockpit of theaircraft.

In order that the invention may be more clearly set forth and betterunderstood, reference is made to the drawings in which:

FIG. 1 is a partial side elevational view of an aircraft and aircraftcanopy embodying the features of the present invention;

FIG. 2 is a top plan view of the structure illustrated in FIG. 1;

FIG. 3 is an enlarged sectional view of the structure illustrated inFIG. 1 taken along the line 33 thereof;

FIG. 4 is an enlarged broken view of the structure illustrated in FIG. 2taken within the circle 4 thereof;

FIG. 5 is an enlarged broken sectional view of the structure illustratedin FIG. 3 taken within the circle 5 thereof;

FIG. 6 is a partial side elevational view of an aircraft and aircraftcanopy illustrating another embodiment of the present invention;

FIG. 7 is an enlarged sectional view of the structureillustrated in FIG.6 taken along the line 7-7 thereof;

FIG. 8 is an enlarged broken view of the structure illustrated in FIG. 6taken within the circle 8 thereof; and

FIG. 9 is an enlarged broken sectional view of the structure illustratedin FIG. 7 taken within the circle 9 thereof.

Referring first to FIGS. 1 through 5 there is shown the cockpit regionof an aircraft fuselage 10 and a canopy 11 that extends aft of a fixedwindshield 12 and covers the cockpit. The canopy 11 comprises a leftcanopy section 13 and a right canopy section 14 that are joined at theirupper edges by connecting hinges l5 and 16 that are connected to andextend completely along the upper edges of the two canopy sections. Thecanopy sections 13 and 14 are composed of a transparent plastic such asan acrylic plastic. A frangible member comprising an elongated shapedround rod 17 is disposed between and adjacent to the upper edges of theleft and right canopy sections 13 and 14 and joins the connecting hinges15 and 16 that are connected to the canopy and extends through theirentire lengths. A

rubber protective covering 18 is attached to the outside of a connectinghinge or 16 above the frangible rod 17 in order to protect the rod. Aflexible side connecting strip 19 is attached to and extends along theentire lower edge of the left canopy section 13. A correspondingflexible side connecting strip 20 is also attached to the lower edge ofthe right canopy section 14 and extends along its entire lower edge. Thelower edges of the side connecting strips 19 and 20 are connectedrespectively to side support rails 21 and 22 that are attached to thefuselage 10. The flexible nature of the connecting strips 19 and 20permit the left and right canopy sections 13 and 14 to pivot outwardwhen they are not joined at their upper edges by the connecting hinges15 and 16 and the frangible rod 17. The side connecting strips 19 and 20may be made from Nylon or some other suitable flexible material.

As illustrated in FIG. 3, a sharp-pointed instrument 23 is connected toa projection 24 on an aircraft ejection seat 25 that is located in thecockpit within the canopy 11. This pointed instrument 23 is designed tostrike the frangible rod 17 as the seat 25 is being projected out of thecockpit during ejection. When the pointed instrument 23 strikes thefrangible rod 17, it causes the entire rod to disintegrate which in turnpermits separation of the connecting hinges 15 and 16 that connect theright and left canopy sections 13 and 14 at their upper edges and thispermits the canopy to be opened. As the aircraft seat continues to moveup during ejection, after the rod 17 has disintegrated, the topprojection 24 will strike the right and left canopy sections 13 and 14and this will cause them to open and pivot outward around the flexibleconnecting strips 19 and 20. The aircraft seat 25 and the airman willthen pass through the opening that results when the right and leftcanopy sections 13 and 14 pivot outward.

As illustrated in FIGS. 4 and 5, the connecting hinges 15 and l6 havegrooves 26 and 27 on their edges that are designed to accept ridges 28and 29, that are bonded or riveted to the hinges, located respectivelyon the upper edges of the right and left canopy sections 14 and 13. Thefrangible rod 17 is centrally located within, and is connected to thecanopy by the connecting hinges 15 and 16 and it joins the hingestogether. The frangible rod 17 should be of sufficient diameter toretain the structural integrity of the canopy 11 when subjected to thenormal design air loads and temperature. The rubber protective cover 18is lightly bonded to a connecting hinge 15 or 16.

In FIGS. 6 through 9 an alternative embodiment of the invention is shownthat employs a single piece canopy 30. The canopy 30 is attached at itslower edges to right and left connecting hinges 31 and 32 that areconnected respectively to right and left side support rails 33 and 34that are attached to the fuselage 10. Frangible members comprisingelongated shaped round rods 35 and 36 are disposed between the two loweredges of the canopy 30 and the fuselage 10 and join the connectinghinges 31 and 32 to the side support rails 33 and 34 and extendthroughout their entire lengths. The frangible rods 35 and 36 aresurrounded and connected to the canopy by the respective hinges 31 and32. As illustrated in FIG. 7, sharp-pointed instruments 37 and 38 areprovided in the cockpit for striking the respective frangible rods 35and 36. These sharp-pointed instruments 37 and 38 are activated by theupward movement of the ejection seat 25 at the beginning of ejection andupon activation they move outward to strike the frangible rods 35 and 36and cause them to disintegrate. After the frangible rods 35 and 36 havedisintegrated, the canopy 30 has essentially been separated from thefuselage l0 and the top projection 24 of the seat as the seat 25 movesupward pushes the canopy upward and removes the canopy from the fuselageso that safe ejection is possible.

The details of the canopy connection of the alternative embodiment areshown in FIGS. 8 and 9. The canopy 30 is secured to the left connectinghinge 32 by means of a ridge 39 that is held within an upper groove 40in the left connecting hinge by bonding or riveting. The left supportrail 34 closes out the bottom of the canopy and acts as part of the maincanopy support framing. The frangible rod 36 is located within theconnecting hinge 32 adjacent to the lower left edge of the canopy 30;and it connects the hinge to the support rail 34. The right connectinghinge 31 is secured to the canopy 30 in the same manner as the leftconnecting hinge and the frangible rod 35 that is similar to rod 36 islocated adjacent to the lower right edge of the canopy 30 and itconnects the right connecting hinge 31 to the right support rail 33 thatis connected to the fuselage 10. When the frangible rods 35 and 36disintegrate after being struck by the sharp instruments 37 and 38, theright and left connecting hinges 31 and 32 are no longer connected tothe respective right and left support rails 33 and 34 and thus thecanopy 30 is free to move in an upward direction so that the canopy canbe opened or removed.

The frangible rods 17, 35, and 36 of this invention also permit thecanopy to be opened without using the ejection seat. In the event theairman needs to open the canopy manually without ejecting, he can strikethe frangible rod 17, 35 or 36 with some suitable sharppointedinstrument and this will cause the frangible rod to disintegrate andallow him to separate the canopy sections 13 and 14in the embodimentshown in FIGS. 1 through 5 or to remove the canopy 30 in the embodimentshown in FIGS. 5 through 9. The airman can also be removed by someoneoutside the aircraft who uses some suitable sharp instrument to strikethe frangible rod 17, 35 or 36 and cause it to disintegrate.

The type of frangible materials that can be used for the frangible rods17, 35 and 36 include various types of tempered glass and specialcompositions of glass ceramics. It is well known that tempered glass hasthe characteristic of great tensile stress in the interior of thematerial which is balanced by compressive forces near the surface. As aresult of this, the entire tempered glass member disintegrates into apulverized material if the compressive layer is penetrated by a blowfrom a sharp instrument. Certain glass ceramics also have theseproperties an can be used for the frangible rods 17, 35 and 36. Theglass ceramics known by the trademark Pyroceramic of the Coming GlassWorks have these qualities and also can be used at higher temperaturesthan tempered glass.

Although the invention has been described in considerable detail withreference to certain preferred embodiments, it will be understood thatvariations and modifications may be made within the spirit and scope ofthe invention as defined in the appended claims.

What is Claimed is:

1. In an aircraft having a cockpit, a canopy covering at least a portionof said cockpit and an elongated frangible rod member comprising amaterial having tensile stress in its interior which is balanced bycompressive forces near its surface that disintegrates if itscompressive layer is penetrated, said elongated frangible rod memberbeing connected to said canopy at a location adjacent to an edge of atleast a portion of said canopy that will assist in permitting theopening or removal of said canopy when said elongated frangible rodmember disintegrates.

2. The apparatus as recited in claim 1 wherein said canopy comprises twosections and said frangible rod member is located adjacent to an edge ofeach of said two sections.

3. The apparatus as recited in claim 2 further comprising meansconnected to at least one of said sections for permitting pivotalmovement of said section when said frangible rod member disintegrates.

4. The apparatus as recited in claim 1 wherein said frangible rod memberis located adjacent to a lower edge of said canopy.

5. The apparatus as recited in claim 4 including a second frangible rodmember located adjacent to another lower edge of said canopy.

6. The apparatus as recited in claim 1 including at least one instrumentlocated within said cockpit for striking said frangible rod member.

7. The apparatus as recited in claim 6 including an aircraft ejectionseat in said cockpit and wherein said instrument is connected to saidejection seat at a point where it will strike said frangible rod memberas said ejection seat is being ejected from said cockpit.

8. The apparatus as recited in claim 7 including at least one connectingmember surrounding at least a portion of said frangible rod member andconnecting said frangible rod member to at least a portion of saidcanopy.

9. The apparatus as recited in claim ll wherein said frangible rodmember comprises tempered glass.

10. The apparatus as recited in claim 1 wherein said frangible rodmember comprises a glass ceramic.

1. In an aircraft having a cockpit, a canopy covering at least a portionof said cockpit and an elongated frangible rod member comprising amaterial having tensile stress in its interior which is balanced bycompressive forces near its surface that disintegrates if itscompressive layer is penetrated, said elongated frangible rod memberbeing connected to said canopy at a location adjacent to an edge of atleast a portion of said canopy that will assist in permitting theopening or removal of said canopy when said elongated frangible rodmember disintegrates.
 2. The apparatus as recited in claim 1 whereinsaid canopy comprises two sections and said frangible rod member islocated adjacent to an edge of each of said two sections.
 3. Theapparatus as recited in claim 2 further comprising means connected to atleast one of said sections for permitting pivotal movement of saidsection when said frangible rod member disintegrates.
 4. The apparatusas recited in claim 1 wherein said frangible rod member is locatedadjacent to a lower edge of said canopy.
 5. The apparatus as recited inclaim 4 including a second frangible rod member located adjacent toanother lowEr edge of said canopy.
 6. The apparatus as recited in claim1 including at least one instrument located within said cockpit forstriking said frangible rod member.
 7. The apparatus as recited in claim6 including an aircraft ejection seat in said cockpit and wherein saidinstrument is connected to said ejection seat at a point where it willstrike said frangible rod member as said ejection seat is being ejectedfrom said cockpit.
 8. The apparatus as recited in claim 7 including atleast one connecting member surrounding at least a portion of saidfrangible rod member and connecting said frangible rod member to atleast a portion of said canopy.
 9. The apparatus as recited in claim 1wherein said frangible rod member comprises tempered glass.
 10. Theapparatus as recited in claim 1 wherein said frangible rod membercomprises a glass ceramic.